Let-off for looms



April 24, 1928.

April 24, 1928. 1,667,221

. K. SAKAMOTO LET-OFF FOR LOOMS Filed May 13. 1926 3 Sheets-Sheet 2 "2". .Jv. i I/ 15 14 v w %/f K. SAKAMOTO LET-OFF FOR LOOMS April 24, 192$.

Filed May 13. 1926 3 Sheets-Sheet 3 f/n z/vfafi Kfa/ramafa A; 7 Z/wf 9 Patented Apr. '24, 1928.

UNITED STATES KYUGORO SAKAMOTO, CF HAMAMATSU, JAPAN.

LET-OFF I FOR LOOMS.

Application filed March 13, 1926, Serial No. 84,463, and in- Japan April 18, 1925.

This invention relates'to improvements in a power loom of the type that a warp beam is unwouml by tension of the warps due to winding of a cloth beam.

lhe object of this invention is to provide a. regulating mechanism which regulates continuously the tension of warps, so that the tension is kept constant regardless of the variation of the diameter of the warps wound on the warp beam.

A further object of this invention is to provide a regulating mechanism which temporarily regulates the tension of the warps when the tension abnormally changes due to accidents. I

A further object of'this invention is to provide a device by means of which all brake members for the warp beam can be thrown out of action in order to allow the beam to turn in any direction at will.

A further object of this invention is to provide a device by means of which a workman can stop the motion of the loom standing at the front side of the machine where he cannot manage a stop handle.

A further object of this invention is to n-ovide a testing attachment 0 detachable from the loom with which the letting out condition of the warps can be tested while the machine is running.

A further ob 'ect of this invention is to provide anindicating mechanism or meter which shows the tension of the warps at each instant.

The characteristic features of this invention are explained hereinafter reference being made to the accompanying drawings, 'inwhich Fig. 1 is a side elevation of a power loom according to this invention, a part of the frame being taken off in order to show the inner parts of the construction. The reed,

healds. shuttles and the operating mecha nisms therefor are also omitted.

Fig. 2 is a side elevation of the same taken on the line IIII in Fig. 3.

Fig. 3 is a front elevation of the loom.

Fig. 4 is a sectional plan of the parts relating to brake members.

Fig. 5 is a detail view of the stopping mechanism showing in plan.

Figs. 6 and 7 are a front elevation and a part sectional plan taken on line VII- VIII. respectively. of the testing attachment which is fitted on the machine, and

Figs. 8 and 9 are a front elevation and a sectionalside elevation, respectively, of the indicator. I

It is well known that the larger the diameter of the warp mass wound on a beam, the more easily the beam can be turned or the warps can be unwound. This is because when the radius of the warps on the beam is large, the arm of moment required to turn the warp beam is large, hence the force orv tension required is small. For this reason, the tension of the warps would be continuously changing throughout the weaving operation should no tension regulating device be provided. The variation of tension, however, is not inversely proportional to the variation of radius of the warps, because the weight of the warp beam, which is the rincipal factor of resistance to the rotation of the beam, includes the weight of the beam itself which does not vary when the radius of the warps varies.

To avoid the variation of tension in the warps, a loom as hitherto known is provided with a friction brake which gives resistance to the rotation of the warp beam, the intensity of the resistance being gradually decreased as the radius of the warp decreases. But such resistance could not give the war s substantially a constant tension since t e variation of its intensity was almost inversel v proportional to the variation of radius of the warp beam.

According to this invention the rotation, of a warp beam is under the control of afriction brake, and the frictional resistance in the brake is regulated by a device which is one of the characteristic features of this invention.

In the drawing, A is a tappet shaft of a loom driven by a power source, and a crank shaft B and all other operating mechanisms are driven by the tappet shaft through intermediate gears. The shaft 1 of the warp beam 3 is mounted rotatively on the frame and a gear on the shaft gears with another gear on a shaft 2. Warps wound on the beam extend over guide rolls. 38 and 42, and

. are wound on a cloth beam 4 after they are woven into cloth. The cloth beam winds up woven warps or cloth step by step as the weaving operation continues, and the ten,- sion of the warps. due to the winding up motion of the cloth beam unwinds the warp beam which is kept from free rotation by means of a riction brake.

The construction of the brake is shown in Figs, 1, 4 and 7. It consists of two friction members 9 and 48, called a friction disc and a friction shoe, respectively, hereinafter. Atan end of the shaft 2 is firmly fixed a brake disc 5, and the friction disc 9 is loosely mounted on a sleeve 7 extending from a bracket 6 on the frame in such a manner that it can slide axially but cannot rotate on the sleeve. The disc 9 is in contact with the inner side of the disc by an inserted friction ring 12 made of a fibre sheetbr the like, which is easily replaced by another one of different diameter or quality when a different condition of friction is required. At the other side of the disc 9 is mounted a rotative ring 8 on the sleeve, the axial movement of which being, however, confined by a nut 13 which is adjustable with respect to its axial position with a set screw- 28. The shaft 2 extends through the sleeve and rotates therein. The circular co-acting face of the ring 8 with the disc 9 consists of one or more saw-toothlike surfaces so as to force the friction disc to move towards the brake disc when the ring 8 rotates in the anticlockwise direction in Fig. 1. The ring 8 has a projection 56, which co-acts with an arm 57 as described hereinafter.

Referring to Fig. 2, a roll 32 at the free end of a lever is in contact with the warps on the beam. A spindle 31, from which the lever extends, is pivoted on the frame, and another lever 33 is connected with the spindle 31 at its crank end. Another end of the lever 33 is linked with a lever 35 pivoted at a stud 35 on the frame, and the free end of the lever 35 is provided with a slot 37 into which a spindle 36 of a frame 22 of a weight 21 is slidably fitted. The frame 22 is supported on a curved lever 18 by a roll provided on the spindle 36. The curved lever is pivoted on a stud 19 and has two arms 23 and 24, at the end of the latter is tied a cord or chain 26. The cord extend; over a guide pulley 17 and is fixed at a point 27 on the frame. The guide pulley is mounted on an arm of a Y shape lever 14, and is adjustable in its osition alone a slot provided in the arm. he Y shape lever is pivoted on a stud 15, and co-operates with other levers 11 and 40 by the other two arms. The lever 11 extends from the ring 8, while the lever 40 is pivoted on a spindle 41, the guide roll 42 being pivoted at the upper part of the lever 40. With these constructions, when the Y shape lever rotates in the clockwise direction the co-operating levers 11 and 40 rotate in the anticlockwise direction, and, when the lever 40 rotates in the clockwise direction the Y shape lever rotates in the anticlockwise direction, conseguently the lever 11 rotates in the clockwise irecti-on.

The cam surface of the lever 18 being slightly declined towards its pivot, the weight frame has a tendency to slide down along the cam lever turning the same in the clockwise direction about its pivot 19 till its tail 23 will get in contact with a projection or stopper 25 on the frame. But the roll 32 being in contact with the surface of the warp beam, the weight is allowed to more towards the pivot as the diameter of the warp beam decreases. At the same time, the Y shape lever is also made to turn in clockwise direction by the tension of the cord or chain, and this turning tendency ofthe lever causes the guide roll 42 to rise against the tension of the warps, and al, 0 causes the ring 8 to turn in ananti-clockwise direction so as to press the friction disc 9 onto the brake disc 5. Since the pressure in the friction brake originates from the turning moment of the cam lever, and the turning moment being directly proportional to the length of its arm, the further the weight-on the cam lever moves from the pivot 19, the more is the frictional resistance in the friction brake. T hercfore, if the cam lever is made of a proper curvature, the variation of the horizontal distance between the weight and the pivot relative to the regular decrease of the beains radius can be made in such-a manner as to give a constant tension to the warps. The curvature of the lever can be determined by experiment.

On the outer face of the brake disc 5 is provided a brake shoe 48 which is held at the upper end of a lever 45 fixed on a spindle 44, which firmly carries other arms 46. and 52. The arm 46 causes the shoe to press on the-periphery of the disc by means of the tension of an adjustable spring 47. Another arm 49 is pivotally mounted on the spindle and is rocked by means of a tappet 51 on the shaft A. At the lowest part of the arm 49 there is provided a small piece 80, which is caused to always project its head sidewards by the tension of acord 82. (See Figs. 3 and 5.) The arm 52 also has a projection 52 at its lowest part, and this projection extends into the path in which the projected head of the piece 80 moves to and fro when the arm 49 rocks. The cord 82 extends from the small piece 80 to a crank shaft 83, which is turned by means of a spring-handle 84'pivoted on a spindle 85'. As long as the cord 82 is stretched and the head of the piece 80 projects, the rocking motion of the arm 49 will drive the arm so as to reciprocally turn the spindle 44. If the cord be slackened a spring 81 on the arm 49 presses in the head of the piece, and the rocking motion of the arm49 ceases to interfere with the arm 52, thus the tappet motion is no longer transmitted to the spindle 44.

When the loom is running in a regular manner, the tappet motion locks the arms Hill I not pulled at all.

.of the warps.

on the spindle 44. While the brake shoe is pressing the brake disc the shaft 52 or the warp beam cannot rotate at all, but while the shoe is out of contact with the disc the beam can be rotated or unwound by the tension At this time, however. the friction disc 5) being in contact with the brake disc 5 under the control of the weight :21 through the intermediate. men'ibers. the warps are unwound so that the tension in the warps is equalized to the braking force. rod 54 extends from the front side of the loom to the rear side. and is provided with a. crank pedal 55 at its rear side, while the front end of the .rod loosely extends through a hole in the free end of an arm 53 which is fixed on the spindle 4 h hen the pedal. which is under the tension of a spring 58, is pressed the rod 54 pulls the arm 5; so as to turn the spindle 4 t and to separate the shoe from the brake disc, but when the arm rocks with the spindle M. the rod is v A short arm 57 is also fixed on the spindle 44. and is rocked w th the spindle. So long as the spindle 4. is being rocked by the tappet. this short arm pushes up a projection 56 of the ring 9 intern'iittently so that the ring is rotated so as to take off the friction between the discs 5 and 9, allowing the disc 5 to rotate freely due to the tension of warps, and the cylinder 3 rotates step by step letting the warps out.

\ When the warp beam is required to rotate in any direction, the machine is at first stopped. Then a workman presses the pedal l is held on the brake disc.

in order to make the brake shoe separate from the brake disc and to take off the pressure in the friction brake. Now the warp beam is free from any brake member and can be rotated by mean of a handle 60 which is connected with'the shaft Qthrough two spindles 61 and 62 and bevel gears 63 and a worm gear 64.

The indicating attachn'le-nt is shown in Figs. 6 and 7. 1f the loom is regularly 0pcrating, the friction disc 5 regularly and intermittently rotates while the brake shoe is separating intermittently from the disc by the tappet motion. In this inventiona pointer is held in an arm projected from the brake shoe and its movements relative to that of the disc is traced on a paper held on the brake disc.

The attachment consists of two parts. one. is mounted on the brake shoe and the other The extreme end of "the shaft 2 extends a little beyond the outer surface of the brake disc. to which a plate 67 with radial arms is prcs'ed' by means of a nut 68. Wis a bracket detachably mounted on the outer side of the brake always has its point in contactwith the surface of the brake disc where a circular sheet ot paper 18 secured by the plate 67. A series of U shape lines 15 traced on the paper 'infa circle, the width between the two legs of each of the U lines being the circumferential movement of the disc, while the height. of the Uli'nes being always constant. If the width of the successive U lines are constant, the length of 'arps unwound per each motion of the reed is constant and the loom is operating regularly.

- A tension meter is shown in Figs. 8 and 9.

short arm 76 is projected from the spindle,

and the arm 73 exteiulsabove the short arm 76; pointer is biased toward an extreme end in the case and the short arm 76 presses the arm 73 down-wards. \Vhen weaving operation is going on, the tappet shaft A and the crank shaft- B revolve, and the cloth beam -1-winds up the woven cloth step by step while healds successively openthewarps to make a shed. and shuttles and a reed play their proper part. A crank-disc 10 on the crank shaft raises and lowers a lever 65, as the shaft revolves. and the lever, in turn, raises and lowers a curved guide plate 39 fixed on' a common shaft (56. The guide plate is raised in order to stretch the: warps when the reed beats whereas the plate is lowered to slacken the warps when the war} 5 are open by healds to make a shat. \Vhile the guide plate is raised the brake shoe is pressing. on the brake disc preventing the warp beam from unwind ng. While the plate is lowered the shoe gets out of contact from the disc and the warp beam can rotate under the control of the friction disc. much as the warps are under a regular tension the guide roll e12 takes its highest osition dueto the pressure originated rom the weight 21 and transmitted through the cord, the Y shape lever and a lever 40. If the warps, however, are under a greater tension the guide roll is pressed down, so that the arm 78 raises its free end, and the pointer moves by the pressure of the spring 79. From the position of the pointer on a scale, the amount of tension in the warps can be easily determined. 7

When an abnormal tension is given to warps by, accident the guide roll is pressed do\vn. and the Y shape lever is rotated in anti-clockwise direction by the arm 40. By

By the pressure of a spring 79 the,

Ill

this means, the friction in the friction brake is decreased so that the warps unwind freely till the warps resume the normal tension and the guide roll assumes the normal position.

The operation of the loom can be stopped b means of a handle 84 manually or a11to matically as in known looms. If it is required to stop the loom by a workman standing at the front. of the machine where he cannot. operate the handle. he merely needs kick an extended end 83 of the crank shaft 83. Then the handle is slightly moved towards the rear and assumes the stop position as if the handle is operated by hand.

In this invention, the continuous controlling mechanism comprising the weight and the cam lever. the temporarily controlling mechanism comprising the guide roll, the disengaging mechanism of the brake members comprising the pedal. and stop mechanism to be operated on the front side are connected by connnon members, and each of them can be operated so that others can co-operate with other devices.

I claim 2-- 1. A warp tension regulating means for looms compris ng the combination of abrake member arranged to restrain the free rotation of the warp beam with a guide roll pivoted on a lever which rocks in accordance lever, in such a manner that the motion of the "am lever due to the decrease in the diameter of the warp beam or the motion of the guide roll due to the abnormal tension of the warps, makes the brake member to release its brake effect on the warp beam.

2. In a warp tension regulating means for looms as claimed in claim 1, a brake member comprising a brake disc firmly held on a shaft which gears with the warp beam, a friction disc slidably but not rotatably mounted on the shaft, and a rotatable ring which cooperates with the friction disc in such a manner that a force transmitted from the cam lever lets the ring press the friction disc toward the brake disc, while a. force transmitted from the guide roll lets the rings withdraw from the friction disc.

3. In a warp tension regulating means for looms as claimed in claim 1, a. Y-shaped lever pivoted on aframe, one arm of said lever coactng with a lever extending from the rotatable ring. and the other two arms coacting with alever on which the guide roll is pivoted, and with a string tied to the cam lever, respectively in such a way that the forces from the guide roll and the cam lever rotates the Y-shaped lever in opposite directions.

4. In a warp tension regulating -1ncans for looms as claimed in claim 1. a brake. member comprising a brake disc tirinly held on a shaft which gears with the warp beam. a friction disc slidably but not 'rotatably mounted on the shaft. a rotatable ring which cooperates with the friction disc in such a manner that av force transmitted from the cam lever lets the ring press the friction disc toward the brake disc. while the force transmit-ted from the guide roll lets the ring withdraw from the friction disc, a sheet of fibre or the like being-inserted between the friction disc and the brake disc so as to be replaceable with another sheet of different diameter or quality when a different condition offriction is required.

5. A warp tension regulating means for looms as claimed in claim 1 including a brake member comprising a brake disc firm- 1y held on a shaft which gears wit-h the warp beam, a friction disc slidably but not r0- tatably mounted on the shaft, a rotatable ring which cooperates with the friction disc in such a manner that aforce transmitted from the cam lever lets the ring press the friction disc toward the brake disc. .while a force transmitted from the guide roll lets the ring withdraw from the friction disc, an indicating mechanism comprising a tracer provided on a brake member which withdraws from braking effect on the brake disc when the latter is rotated by rotation of the warp beam.

In testimony whereof I hereunto affix my signature.

KYUGORO SAKAMOTO. 

